If your car has high mileage, I would just replace the whole control arm instead of just the bushings. Reason being that the balljoints are worn and they cannot be replaced unless you get a whole new arm. I'm not sure how they quoted you $2000 installed for the arms since oem Lexus ones are about $420/each, oem Toyota Supra (93-96) ones are about $200/each, and 97-98 Supra arms are about $350/each since they are aluminum. Just get the parts yourself for alot cheaper and have them install it.
93-98 Supra arms
~ $400/pair supra arms + $250 labor + $80 alignment = $730, therefore $1270 for the ac compressor/labor?
OEM Lexus
~ $840/pair lexus arms + $250 labor + $80 alignment = $1170, there for $830 for the ac compressor/labor?
Seems pretty steep to me.